The process to make conventional threads in which one starts with the web of the fiber to be used obtained by carding, so that initially a carding cord is obtained which is the base from which the twisted and stretched thread is obtained, is known. The fiber of said cord must have long hair so that upon twisting it and stretching it, it does not break. This implies the inconveniences that all the very short fibers of the material that is used are not made use of, and that the thread obtained is too expensive, especially if disposable fabrics are to be made therefrom.
On the other hand, unwoven disposable elements that replace traditional textile pieces such as napkins, table cloths, paper tissues, etc. are known. Said unwoven elements are comprised of an accumulation of layers of cellulose with different finenesses with specific properties of absorption, resistance and other features. These cellulose layers are joined by means of acrylic chemical products or the like. The cited unwoven elements have certain inconveniences, such as their resistance and consistency drop upon becoming wet becoming unuseable for the most part, or their touch differs greatly from that of textile pieces which they replace, or they cause allergies in users.
Low cost fabric elements whose cost reduction is determined by the reduction of the number of weft thread per centimeter are known. Said fabrics manufactured at a low cost have the inconvenience that they have few threads per unit of length and between said threads big holes that reduce the continuity of the obtained fabric, making it unacceptable for many uses for which its use would be desirable, are established.
Concerning compound threads the following documents have been found in the corresponding search:
European patent application EP-A-0339965 PA1 U.S. patent application U.S. Pat. No. 3,835,638 PA1 German patent application DE-A-28 39 941 PA1 Abstract of Japanese patent application JP-A-022891376 PA1 Abstract of Japanese patent application JP-A-61296134.
The document EP-A-0339965 refers to a bushy thread that is comprised of a core thread with a total denier of 140 to 1,260, an adhesive that is applied to the core or carrier thread, as well as bushy fibers (flies of fibers) with a cutting length of 0.5 to 3 mm which is intermatted to an intermatting density of no less than 30,000/cm.sup.2. Said thread is obtained by means of a process in which the intermatted fibers are applied by means of an adhesive layer to the core thread. Electrostatic fields in which forces of attraction and forces of repulsion alternately are also applied, changing the polarity of some pairs of electrodes or placing electrostatic fields of attraction and repulsion sequentially.
The document U.S. Pat. No. 3,835,638 refers to a process for continuous forming of different types of carrier threads. Said process basically comprises an electrostatic coating of the periphery of a center element with individual fibers. The individual fibers are expelled through a duct towards an electric field generated by a suitable unit. Besides, a tank which, according to this document, contains a reticulating agent, is included, so that the original center element passes through the tank.
The document DE-A-28 39 941 refers to a device for an electrostatic process of textile fiber projection, which permits bushy thread to be manufactured. Said device basically comprises a projection or piling chamber, through which a carrier thread passes, whose top and bottom are provided with respective electrodes, and that has an endless conveyor belt comprised of fiber glass for the supply of bushy material, including a transport organ positioned in a plane inferior to the top electrode and moveable with regard to a device for eliminating bushy material by means of which the bushy material adhered to the cited transport organ is eliminated. As indicated in this document, the purpose of the device is to prevent that in the top chambers of the apparatus that are used in electrostatic textile fiber projection processes for manufacturing bushy thread, irregular accumulations of bushy fibers are produced in the top electrodes of the projection chambers, as well as to prevent, even when there is a small accumulation, uncontrolled variations of the electric-camp from being produced. On the other hand, this document cites as prior art devices for electrostatic textile fiber projection, in whose projection chambers the bushy material is applied on the carrier thread provided with an adhesive agent.
The document JP-A-022891376 refers to a bushy product with an ion exchange capacity and to the manufacturing process thereof. The product is obtained by means of a process that consists of introducing a core or carrier thread with a total denier of 50 to 50,000 whose periphery is coated with an adhesive, in an area in which there is at least one pair of electrodes of which to one of them a positive voltage is applied and to the other one a negative voltage is applied, intermittently changing the polarity of said electrodes to generate an electrostatic field in which forces of attraction or forces of repulsion act alternately. During the process pulp that is prepared by cutting a fibrous material with an ion exchange capacity at a length of 0.1 to 3 mm is applied to the adhesive layer of the carrier thread.
Japanese patent application JP-A-61296134 refers to a compound thread of a mixture of cotton and feathers that is obtained by adding to the feathers a water-soluble adhesive agent, or a hydrophilous organic solvent, to obtain feather fibers with a volumen ratio of less than 100 cc/g. These fibers are mixed with cotton fibers. The resulting thread is water-repellent and maintains heat.
All of these documents can be considered as ones merely belonging to the technological field of the invention, in other words, they define a prior art concerning the same sector, but they do not anticipate the present invention, since none of the documents provide for the fiber added to the carrier thread having a strip-form shared by several parallel carrier threads, useable in itself, and/or from which final compound threads are extracted, resulting from the cutting of said strip. Neither do they include certain features existing in the present invention that will be described hereinafter.